Implement Clear Browser Data for Mac as an app modal dialog. Uses the profile of the given window or the default profile if run with no windows open. Add a setter to the throbber so it can be used in a nib file.
BUG=none
TEST=clear browser functionality (note that clearing passwords doesn't work) and checkbox persistance.
Review URL: http://codereview.chromium.org/112065

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@17186 0039d316-1c4b-4281-b951-d872f2087c98